The present invention relates to a mounting assembly for mounting a vehicle interior rearview mirror to a vehicle mount. The present invention further relates to a high strength-to-weight part forming part of such mounting assembly, and methods of forming same.
For the last 30 years or so, one common mounting assembly for vehicle interior rearview mirrors has been a tubular dual ball-and-spring support construction, such as disclosed by U.S. Pat. No. 3,367,616 to Bousch et al. With that construction, a spring biases vehicle-mounted and mirror-mounted balls into engagement with opposite ends of a tube. The mirror can be adjusted by rotation of each of the two balls, though it is usually desirable to adjust the mirror at the mirror-mounted ball. However, the same spring biases both balls and as such both will rotate at the same level of force unless there are different clamp members or ball clamp members of the same construction but made of materials having different coefficients of friction. Other dual ball mounts of this type are disclosed by U.S. Pat. No. 4,646,210 to Skogler et al., U.S. Pat. No. 5,327,288 to Wellington et al., and U.S. Pat. No. 5,521,760 to DeYoung et al. It is sometimes desirable to provide different levels of force at the opposing ends of a mirror mount to facilitate adjustment by a vehicle driver.
Vehicle interior rearview mirrors of the automatic dimming type are conventionally about twice as heavy as standard rearview mirrors. For this reason, it is desirable for the mirror-mounted ball to be located relatively close to the center of gravity of the mirror in order to minimize the torsional effect of the mirror weight on the ball and to facilitate adjustment of the mirror. An improvement is desired that facilitates positioning the ball close to the center of gravity of the mirror, yet that maintains the low cost and durability of the mounting assembly.
Modern interior rearview mirrors of vehicles are commonly mounted to a vehicle front window or to an overhead console. However, in such a position, the mirror-mounting assemblies are subject to conflicting design criteria. For example, it is desirable to construct mounting assemblies having a minimized length, so that the mirror is not adversely affected by vibrational problems associated with long cantilevered support arms. At the same time, the mounting assemblies must be long enough to permit adequate angular adjustment of the mirror without interference from the vehicle front window or overhead console, and further must be long enough to allow quick assembly, mechanically as well as electrically.
Another objective is to minimize weight of the mounting assembly. Low weight is an important objective of modern vehicle manufacturers, because it helps manufacturers meet curb weight and fuel mileage goals, which items are due in part to customer demand and also due in part to government incentives to manufacture vehicles that achieve high fuel mileage and have a low curb weight. Nonetheless, even low-weight mounting assemblies must maintain sufficient rigidity and stiffness to prevent unacceptable amounts of mirror vibration, and further must be able to provide the long term durability necessary to allow thousands of angular adjustments as different vehicle drivers adjust the mirror for their individual use.
As noted above, known mounting assemblies of interior rearview mirrors typically include one or more ball-and-socket type connections. It is important that each of the ball-and-socket connections permit easy angular adjustment, so that all drivers, even those who have relatively weaker arms and wrists, can adjust the mirror to an optimal angular position. At the same time, the ball-and-socket connections must securely hold the newly selected angular positions, once they have been adjusted. Accordingly, it is very important that the torsional frictional forces on the ball-and-socket connections set by design goals are consistently met with low product variation. It is also important that the ball-and-socket connections maintain the designed torsional frictional forces over their life and over a wide range of temperature variation while the vehicle is in service. Still further, it is preferable that the feel provided during any adjustment movement be very uniform and smooth, because vehicle drivers interpret this as an indication of the quality of the mirror, as well as of the quality of the vehicle as a whole.
Accordingly, a mounting assembly solving the aforementioned problems and having the aforementioned advantages is desired, which mounting assembly preferably is compact and maintains maximum adjustability, while minimizing its effective length and weight, and that is mechanically simple and utilizes low cost parts and manufacturing processes.